Daroukh, M.A.L and Vashook, V.V. and Ullmann, H. and Tietz, F. and Arulraj, I. (2003) Oxides of the AMO3 and A2MO4-type: structural stability, electrical conductivity and thermal expansion. Solid State Ionics, 158. pp. 141-150. ISSN 0167-2738

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Abstract

The structural and chemical stabilities, electrical conductivity, and thermal expansion of the A2 aAaVMO4 x oxides (A= La; AV= Sr; M= Mn, Fe, Co, Ni) with the perovskite-related K2NiF4-type structure were investigated and compared with the characteristics of perovskite-type oxides AMO3 x containing the same cations. The K2NiF4-type manganites, ferrites, cobaltites and nickelates are assumed to be reduction products of the corresponding perovskite-type oxides. The thermodynamic stabilities, in terms of reversible oxygen desorption, were higher than those of the corresponding perovskite-type oxides. Within the range of oxygen partial pressure ( pO2) from air to argon/H2/H2O, the oxidation states of the M cations were determined. The comparison of the oxidation states of M in AMO3 x and (AMO3 x)AO gives evidence on the stabilizing influence of the AO interlayer on the perovskite layer. The electrical conductivity of the A2MO4 oxides was of p-type and reached values close to 100 S cm 1 at high oxygen partial pressures and 800 jC for nickelates and cobaltites. The thermal expansion of K2NiF4-type oxides is generally lower than that of the comparable perovskite-type oxides.

Item Type:	Article
Uncontrolled Keywords:	Oxides; Perovskite structure; Chemical stability; Electrical conductivity; Oxygen transport; Thermal expansion
Subjects:	Fuel Cells
Divisions:	UNSPECIFIED
Depositing User:	ttbdar CECRI
Date Deposited:	24 Mar 2012 07:45
Last Modified:	24 Mar 2012 07:45
URI:	http://cecri.csircentral.net/id/eprint/915

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